| Orig Im | Select Original Image. |
| Hough xfm | Select Hough transform image. |
| Line color! | Lines and sinusoids are drawn in this color. Click to change to the menu selected color: |
| Hough Click | If ON, click and drag on Hough Xfm, see corresponding line on Original image. Draws line with line color on mouse up. |
| Orig Click | If ON, click and drag on Original image, see sinusoid on Hough Xfm image. Draws sinusoid with line color on mouse up. |
| Square Gratings | Types line spacings in each direction and the angle between them. See example. |
| Spot R! | Vertical halfwidth of spot. (Approximate - this sets the region for the measurements.) |
| Min Pct! | Estimate of minimum distance between spots. |
Description of Hough Transform
The Linear Hough Transform is often represented this way:
where r (rho) and theta are the distance and inclination of a line in the image (below, left). Thus, in Hough space (below, right), the line corresponds to a single point.
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Examples:
The Linear Hough Transform maps straight lines into points. Points are easier to locate (to blob) than are lines, using image processing techniques.